1. Technical Field
The present disclosure relates to a fuel cell system.
2. Description of the Related Art
In a fuel cell system using hydrocarbon as raw material gas, the raw material gas is reformed through reforming reaction. The raw material gas contains, for example, a sulfur compound as odorant and the sulfur compound can cause degradation of a reforming catalyst used for promoting the reforming reaction. For preventing the degradation of the reforming catalyst, a desulfurization device for removing the sulfur compound contained in the raw material gas is utilized.
For the desulfurization device, an absorbent desulfurizer and a hydro-desulfurizer are typically used. A hydro-desulfurizer converts a sulfur compound into a hydrogen sulfide, which is easier to be absorbed, and removes the hydrogen sulfide by causing it be absorbed to absorbent, and has the advantage of higher absorption capacity than the absorbent desulfurizer.
For example, Japanese Unexamined Patent Application Publication No. 2011-216308 describes a technique for removing sulfur compounds in raw material gas through hydrogenation reaction by passing hydrogenated raw material gas through a hydro-desulfurizer heated to about 150° C. to 400° C. with heat transfer from an internal casing.
As another example, in a technique described in Japanese Unexamined Patent Application Publication No. 2013-229120, a desulfurizer heating unit through which combustion exhaust gas flows is provided outside a hydro-desulfurizer so as to heat the hydro-desulfurizer, and the raw material gas which is to enter the hydro-desulfurizer exchanges heat with the raw material gas discharged from the hydro-desulfurizer. The raw material gas can thereby be pre-heated before it enters the hydro-desulfurizer and also the hydro-desulfurizing agent in the hydro-desulfurizer can be kept at an appropriate temperature.
Japanese Unexamined Patent Application Publication No. 2010-272333 describes a technique in which a hydro-desulfurizer is accommodated in a jacket and combustion exhaust gas flows through the jacket.